1. Field of the Invention
The present invention relates to an apparatus and a method used for an artificial skiing ground, for example, and particularly relates to an artificial snow producing and releasing apparatus for crushing flaky or platy pieces of ice produced by primary crushing into smaller snowflaky pieces of ice and releasing it far away, and the method thereof.
2. Description of the Related Art
A prior artificial snow producing and releasing apparatus is an apparatus for producing artificial snow by crushing lumps of ice by means of a blast-type crusher such as an ice crusher into finer snow mingled with ice and releasing it.
An apparatus shown in FIG. 7, for example, has a structure in which a rotor blade 34 for crushing is provided inside a casing 33 provided on a base 36 and the rotor blade 34 is covered with the casing 33. A supply port serving both as a blast port 30 from which a blast for blowing artificial snow 38 away is supplied and a supply port 31 from which lumps of ice which are raw materials are supplied is provided at one end on the base 36 at the lower end of the casing 33, and a discharge port 32 from which the artificial snow 38 composed of crushed ice is blown away is provided at the other end on the base 36 at the lower end of the casing 33 on the opposite side to the supply port 31. Lumps of ice 37 supplied together with a blast from the blast port 30 on the base on the right side of FIG. 7 are beaten against the base 36 by the rotor blade 34 rotating at high speed in the casing 33 and crushed into snow mingled with ice to make the artificial snow 38, and subsequently the artificial snow 38 is blown away to a skiing slope from the discharge port 32 by the blast and sprinkled over the slope.
In another type of blast-type crusher shown in FIG. 8, a supply port 41 from which lumps of ice are supplied and a blast port 40 from which a blast for delivery is supplied are provided at separate positions of a casing 43 of the blast-type crusher, and the supply port 41 for lumps of ice 47 is provided in the upper portion of the casing 43. While the lumps of ice supplied from the supply port 41 are rotationally forwarded by a rotor blade 44 for crushing which rotates at high speed by means of a rotating shaft 45, the lumps of ice are beaten and crushed by the rotor blade 44 and sent to the blast port 40 at the lower end of the casing, and further finely smashed against the base 46 by the rotor blade 44 into snow mingled with ice to make artificial snow 48, and discharged from a discharge port 42 on the opposite side at the lower end of the casing 43 and blown away by a blast.
Japanese Patent Laid-open No. Shou 62-182567 discloses an apparatus for shaving the tip of a large lump of ice into with a rotary cutter crusher to produce artificial snow composed of snow mingled with ice while moving the lump of ice forward by a conveyor, sending the artificial snow to a rotary snow throwing machine with a built-in impeller at the back, delivering it into a cylinder by the rotation of the centrifugal impeller, and further adding air from an air jet port to the delivered artificial snow within the cylinder to throw the artificial snow from within the cylinder, or instead of providing the air jet port within the cylinder and adding air to throw the artificial snow from within the cylinder, sucking in air from the opposite side to an artificial snow suction port with the impeller as a double suction type centrifuge to throw the artificial snow from within the cylinder.
These prior blast-type crushers have the following disadvantages.
In the crusher shown in FIG. 7, unevenness occurs in the size of particles of ice crushed by the rotor blade 34 due to variation in the supply quantity of the lumps of ice 37 to be supplied to the casing 33 from the blast port 30. Further, when the supply of the lumps of ice 37 is excessive, there is the possibility that a space between the blast port 30 and the discharge port 32 is blocked, and thus more power than necessary is required in order to rotate the rotor blade 34 at high speed.
In the blast-type crusher shown in FIG. 8, in addition to the disadvantage of the aforesaid blast-type crusher shown in FIG. 7, when the blast power at the blast port 40 is raised in order to release crushed ice far away, not all the blast power inside the casing 43 flows to the discharge port 42, but part of the blast power also flows backward to the supply port 41 side and leaks out from the supply port 41, and hence the blast power necessary for releasing the artificial snow 48 composed of crushed ice from the discharge port 42 reduces. As a result, the artificial snow 48 can not be released far away, thereby requiring still more power than necessary.
In the apparatus disclosed in Japanese Patent Laid-open No. Shou 62-182567, the front face of the large lump of ice is shaved with the rotary cutter crusher to make artificial snow composed of snow mingled with ice while being moved forward by a conveyor. The apparatus, however, is extremely large-sized, and the producing capacity thereof is inferior in efficiency to that of the aforesaid apparatus in which the pieces of ice are beaten by the rotor blade and the base. The obtained artificial snow is supplied to the rotary snow throwing machine by sending the artificial snow flying by only mechanical force of the rotary cutter. Consequently, a large quantity of artificial snow can not be supplied, and therefore supply efficiency is low. Accordingly, even if the artificial snow is sent into a chute used for letting snow fall in the rotary snow throwing machine by centrifugal force of the impeller, air needs to be further jetted halfway in the chute. In the apparatus in which the double suction type rotary snow throwing machine is used in place of the aforesaid rotary snow throwing machine, air sucked into the double suction type rotary snow throwing machine from an opening on the opposite side to the side of the supply port for the artificial snow is sent into the chute, with the disadvantage that a large quantity of artificial snow can not be supplied by sending it flying with the rotary cutter left unsolved. Therefore, delivery power necessary for delivering the artificial snow and air into the chute needs to be given to the double suction type rotary snow throwing machine itself, which is a burden for the double suction type rotary snow throwing machine itself, thus requiring large increase in size of the machine. Consequently, there arises a disadvantage that the apparatus becomes still larger in size combined with the aforesaid increase in size of the rotary cutter crusher. Further, in the apparatus disclosed in Japanese Patent Laid-open No. Shou 62-182567, the artificial snow composed of crushed ice to be supplied to the rotary snow throwing machine is not supplied while being sent by means of air from the beginning, whereby only the artificial snow touches the impeller of the rotary snow throwing machine. Alternatively, in the double suction type rotary snow throwing machine, a partition is provided in the impeller to separate the artificial snow and air so that the artificial snow and air do not abut on the same portion of the impeller. As a result, the artificial snow, that is, flaky pieces of ice adhere to a beating portion of the rotating impeller, which causes the impeller to lose its balance and increases the load. Under a worse situation, an excess current occurs in a drive motor, which requires the stop of operation. Especially, since the flaky piece of ice is scaly ice with a thickness of 2 mm to 3 mm and a size of 100 mm2 and the surface area thereof is large, it has a property of being prone to adhere as compared with another block-shaped ice. Accordingly, hitherto there never exist any appropriate snow producing and throwing apparatus for which flaky pieces of ice are used.
Artificial snow produced and thrown by the prior apparatus is corn snow and not firm snow, and hence in a slope for skiing and the like, it is far behind natural snow in property.
An object of the present invention is to provide a method of efficiently supplying flaky or platy pieces of ice by primary crushing to a secondary crusher with strong discharge pressure of a forced blast and secondarily crushing the supplied pieces of ice into smaller pieces to produce firm artificial snow suitable for slope skiing and similar to natural snow, and throwing the artificial snow far away by an increase in the discharge pressure of the forced blast in addition to centrifugal force given from a rotor blade, and a compact apparatus for carrying out the method and efficiently producing and throwing a large quantity of artificial snow.
To attain the above object, the main aspect of the present invention is an apparatus for producing artificial snow from flaky or platy pieces of ice and releasing the artificial snow, comprising a rotating shaft, a rotor blade having a plurality of blades disposed along the direction of rotation of the rotating shaft, means for rotationally driving the rotating shaft, a casing enclosing the rotor blade and having a supply port from which the pieces of ice and a forced blast are supplied toward the rotor blade in the shaft direction of the rotating shaft and a delivery port from which the artificial snow produced from the pieces of ice and the forced blast are sent out nearly in the direction of a tangent of the rotational outer periphery of the rotor blade.
These objects and still other objects and advantages of the present invention will become apparent upon reading the following specification when taken in conjunction with the accompanying drawings.